Ionization Balance for Ni Ions under Coronal Equilibrium

Abstract

The available electron-impact ionization cross-sections and recombination rate coefficients for Ni ions are reviewed, and the fit parameters to Younger's empirical formula for the ionization cross-sections of Ni 1+, Ni 3+, and Ni 5+ through Ni 8+ are updated. Also presented are the calculations of the ionization balance for the ions under coronal equilibrium, The calculated ionic abundance fractions are compared with those of previous work. A possible implication of the long-standing problem of Nickel overabundances in several classes of astronomical objects is also discussed.